Bispecific antibodies for cancer therapy: The light at the end of the tunnel?

In the paper

“Human anti-mouse antibody (HAMA) responses were seen in most treated patients, which severely decreased the efficacy of the murine molecules and excluded the possibility of multiple administrations.”

In the paper

“Such molecules would be capable of retargeting a large variety of payloads to cancer cells.”

In the paper

“This approach has the advantage of avoiding a direct systemic injection of bsAb in the patient, thereby significantly minimizing toxicity associated with free murine Fc bearing molecules. 19”

What the sources say

• Not checked yetcites [19] source

In the paper

“In short, this Fc adds two crucial functions to regular anti-CD3 x target bsAbs: additive tumor killing capabilities through the efficient recruitment of macrophages and NK cells and, most importantly, efficient co-stimulation of T cells through direct contact with accessory cells such as macrophages of efficacy”

In the paper

“Moreover, EpCAM is very often on cancer stem cells, a very attractive feature for a tumor marker. 24”

What the sources say

• Not checked yetcites [24] source

In the paper

“Two Phase 1 clinical studies performed with this molecule led to one complete remission (CR) and one partial remission (PR) in a group of 15 treated patients; 14 this was followed by one CR and three PR in a second clinical trial. 15”

What the sources say

• Not checked yetcites [14] Hartmann F, 1997, Blood source
• Not checked yetcites [15] Hartmann F, 2001, Clin Cancer Res

In the paper

“EpCAM is also expressed in normal cells, but is predominantly located in intercellular spaces where epithelial cells form very tight junctions.”

In the paper

“The first studies of bsAbs highlighted two major limitations of the first generation molecules, including the difficulty of producing large, homogeneous batches, and the lack”

In the paper

“The second specificity of these bsAbs was directed against FcγRI (CD64), which is notably expressed on monocytes and macrophages and upregulated upon activation on neutrophils.”

In the paper

“They are abundant, efficiently proliferate upon activation, capable of killing multiple times 16 and efficiently infiltrate tumors, but do not express Fcγ receptors.”

What the sources say

• Not checked yetcites [16] source

In the paper

“A series of clinical trials were also performed with chemically linked bispecific (Fab')2 molecules targeting the breast and ovarian cancer tumor antigens HER2 or EGFR, [9][10][11][12] which are overexpressed in many epithelial tumors such as colorectal, head and neck, bladder, renal, non-small cell lung carcinoma.”

What the sources say

• Not checked yetcites [9] source
• Not checked yetcites [10] source
• Not checked yetcites [11] source
• Not checked yetcites [12] source

In the paper

“EpCAM (CD326) is expressed on essentially all human adenocarcinoma, certain squamous cell carcinoma, retinoblastoma and hepatocellular carcinoma.”

In the paper

“Surprisingly, the resulting hybrid rat/mouse Fc portion efficiently interacted with activating human Fc receptors (FcγRI and FcγRIII), but not inhibitory ones (FcγRIIB), thereby reaching the goal that other groups had hoped to achieve using human Fc engineering. 22,23”

What the sources say

• Not checked yetcites [22] source
• Not checked yetcites [23] Zeidler R, 1999, J Immunol source

In the paper

“Biological effects were seen in some clinical trials of bsAbs MDX-210 (targeting Her2 and CD64), MDX-H210 (humanized version of MDX-210) and MDX-447 (targeting EGFR and CD64), but none of these treatments led to consistent antitumor activity. [9][10]0][11][12]”

What the sources say

• Not checked yetcites [9] source
• Not checked yetcites [10] source
• Not checked yetcites [11] source
• Not checked yetcites [12] source

In the paper

“The first anti-CD3 bsAbs were thus administered in combination with anti-CD28 antibodies, but the combination yielded mixed results. 18”

What the sources say

• Not checked yetcites [18] source

In the paper

“Interestingly, it was shown that bsAb-retargeted PACTs can divide and secrete cytokines upon restimulation with target cells, while retaining their specificity and cytotoxicity for more than two weeks, which might be an important feature for therapeutic settings. 20”

What the sources say

• Not checked yetcites [20] source

In the paper

“Catumaxomab, which targets the tumor antigen EpCAM, was the first triomab produced.”

In the paper

“Without the secondary signal given by the interaction between CD28 and one of its ligands (e.g., B7), T cells are not fully activated, and might even become anergic. 17”

What the sources say

• Not checked yetcites [17] source

In the paper

“The investigators used this approach to create an anti-CD3 x anti-EpCAM bsAb, and demonstrated that this antibody was capable of binding to target cells and human T cells, but was also capable of activating dendritic cells (DC), inducing NK-dependent ADCC and stimulating tumor cell phagocytosis by macrophages. 22,23”

What the sources say

• Not checked yetcites [22] source
• Not checked yetcites [23] Zeidler R, 1999, J Immunol source

In the paper

“limitations in their modes of action, including redundancy of molecular pathways leading to cancer cell survival, effects of the microenvironment, suboptimal interaction with effector cells due to alternative Fc glycosylation or Fc receptor polymorphism, activation of inhibitory receptors, and competition with circulating IgG. 2”

What the sources say

• Not checked yetcites [2] source

In the paper

“By using an original subclass combination (mouse IgG2a and rat IgG2b), they demonstrated a preferential speciesrestricted heavy/light chain pairing, in contrast to the random pairing in conventional mouse/mouse or rat/rat quadromas, as well as use of sequential pH elution on protein A to easily separate the desired bsAb from the parental mAb.”

What the sources say

• Not checked yetcites [21] Lindhofer H, 1995, J Immunol source

In the paper

“Although difficult to produce in E. coli, this 60 kDa molecule is well-expressed by mammalian cells.”

In the paper

“Below the maximum tolerated dose (200 μg), side effects, including fever, nausea and vomiting, were predictable, limited, manageable and mostly fully transient. 27”

What the sources say

• Not checked yetcites [27] Parsons S, 2009, J Clin Oncol

In the paper

“In comparison, rituximab demonstrated a significantly lower B cell eradication rate. 31”

What the sources say

• Not checked yetcites [31] source

In the paper

“This effect was dependent on the presence of the hybrid Fc, and involved a humoral response directed against the non-transfected (EPCAM -) tumor cells.”

What the sources say

• Not checked yetcites [25] source

In the paper

“This triomab possesses the same hybrid Fc portion as catumaxomab, and displays the same efficiency in vitro. 29”

What the sources say

• Not checked yetcites [29] source

In the paper

“All mice rechallenged on day 144 after the primary challenge were still able to reject the tumor, indicating the high efficacy and long duration of the antitumor response.”

What the sources say

• Not checked yetcites [25] source

In the paper

“Surprisingly, no bispecific diabodies have been tested so far in clinical trials.”

In the paper

“In the nineties, advances in antibody engineering provided innovative solutions antibody design problems, allowing production of small antibody fragments recapitulating the entire binding activity of the parent molecule (Fig. 1).”

In the paper

“These molecules can be expressed at high yields in bacteria and have been shown by crystallography experiments to adopt several conformations. 35”

What the sources say

• Not checked yetcites [35] source

In the paper

“Moderate anti mouse and anti rat responses were seen in the majority of the patients but they do not seem to affect the efficiency of the treatment. 26”

What the sources say

• Not checked yetcites [26] source

In the paper

“Tandem scFvs (TaFv) are two scFv fragments linked by an extra peptide linker that is expected to confer good flexibility to each fragment.”

In the paper

“Expressed on all stages of B cell development from pre-B cells through memory cells, but not on either pro-B cells or plasma cells, CD20 represents an attractive target for the treatment of B cell malignancies.”

In the paper

“f note, two other triomabs, targeting melanoma-associated proteoglycans or melanoma-associated gangliosides (GD2 and GD3), 33 are in preclinical studies as potential treatments for malignant melanoma.”

What the sources say

• Not checked yetcites [33] source

In the paper

“T cell activation and tumor cell killing occurred in an entirely autologous setting, i.e., without additional effector cells, in 5 of 8 samples.”

What the sources say

• Not checked yetcites [31] source

In the paper

“This difference can probably be explained by the mode of action of these antibodies.Trastuzumab triggers NK-mediated ADCC, while ertumaxomab relies on T cell mediated killing and the interaction between T cells and accessory cells, as demonstrated by the release of proinflammatory cytokines such as IL-6, IFNγ and TNFα.”

In the paper

“Exposure to ertumaxomab led to the efficient lysis of cells expressing very low amount of tumor antigen, whereas trastuzumab was completely ineffective even at high concentration. 30”

What the sources say

• Not checked yetcites [30] source

In the paper

“This molecule spontaneously forms stable dimers, and was shown to be capable of inducing T-cell activation and effective tumor-cell killing in vitro and in vivo without a signal through the TCR/CD3 complex, a so called”

What the sources say

• Not checked yetcites [40] source

In the paper

“Ertumaxomab is triomab targeting HER2, a well-characterized breast tumor marker that is also targeted by trastuzumab (Herceptin).”

In the paper

“BiTEs, or bispecific T cell Engagers, are made by fusing an anti-CD3 scFv to an anti-TAA scFv via a short five residue peptide linker (GGGGS).”

In the paper

“This molecule demonstrated outstanding in vitro properties, including efficient cytotoxicity induced by extremely low concentrations of bsAb (10-50 pg.mL -1 , i.e., subpicomolar), at low effector:target ratio (2:1), and in only four hours, without the need for pre-stimulation of T cells or, most surprisingly, the need of co-signaling (e.g., through CD28).”

What the sources say

• Not checked yetcites [45] Loffler A, 2000, Blood source

In the paper

“Bi20 triomab utilizes the same hybrid Fc portion as catumaxomab and ertumaxomab, and targets CD20.”

In the paper

“It should be highlighted that cumulative doses of several milligrams were sufficient to lead to the notable response in patients, whereas conventional antibody treatments, such as rituximab, consume gram amounts per treatment cycle.”

In the paper

“Exceptionally high tumor blood ratios were observed, ranging from 13 at 0.5 h to 395 at 24 h, with high tumor uptake of 30% ID/g, whereas the levels in blood and normal tissues, except kidney, were <1% ID/g at 1 h after injection.”

What the sources say

• Not checked yetcites [61] source

In the paper

“Blinatumomab, a murine antihuman CD3 x anti-human CD19 was the first BiTE developed and is the most advanced BiTE in clinical trials.”

In the paper

“The absence of a need for co-signaling through CD28 for these BiTEs might also be explained by the observation that among all T cell subtypes, CD8 + effector memory cells CD45RO + (TEM) and CD8 + effector memory CD45RA + (TEMRA) contribute the most to BiTE activity, whereas naïve T cells do not contribute at all to the killing efficiency. 50”

What the sources say

• Not checked yetcites [50]

In the paper

“MT110, an anti-human EpCAM x anti-human CD3 TaFv, was the second BiTE tested in clinical trial and the”

In the paper

“This result is remarkable since MRD positive ALL patients have very limited treatment options, and around 60% of patients die within 2 years, with a median time to hematological relapse of only 4.1 months.”

In the paper

“Since MT110 does not activate murine T cells, this result suggests that tumor resident human T cells, being tolerized or anergized, could be reactivated, and were present in sufficient number to eliminate the xenograft. 56”

What the sources say

• Not checked yetcites [56] source

In the paper

“Thirteen out of 16 evaluable patients (81%) became minimum residual disease (MRD) negative, with ongoing responses lasting for up to 47 weeks on May the 25 th 2009 (data presented in Recombinant Antibodies meeting, June 2009, Cologne).”

In the paper

“Despite this extreme efficiency, the killing remains strictly target-cell dependent, and T cells cannot be activated in the absence of target cells, even at concentrations exceeding EC 50 values by several thousand fold. 48”

What the sources say

• Not checked yetcites [48] source

In the paper

“Interestingly, this trial was associated with significantly reduced toxicity compared to NHL patients at the same dose level, suggesting that toxicity might be correlated to the number of target cells present in patients, rather than to the BiTE molecule itself.”

In the paper

“Upon association, two disulfide bonds are created, resulting in a covalent complex that is stable for more than a week at 37°C in human serum.”

What the sources say

• Not checked yetcites [61] source

In the paper

“The first described bsAb built using the DNL method was a molecule of 157 kDa, devoid of Fc fragment, comprising two Fab fragments derived from humanized anti-human CEA mAb hMN-14 and one Fab fragment from humanized mAb h679 that is able to strongly bind the hapten histamine-succinyl-glycine (HSG).”

What the sources say

• Not checked yetcites [61] source

In the paper

“This can be used to efficiently create any kind of bsAb, but was so far used to create bispecific molecules dedicated to radioimmunotherapy.”

What the sources say

• Not checked yetcites [61] source

In the paper

“Later, studies performed in chimpanzees showed that repeated 2 h treatments with doses as low as 0.1 μg.kg -1 were welltolerated, and led to cumulative depletion of peripheral B cells due to fully reversible T cell activation. 53”

What the sources say

• Not checked yetcites [53] source

In the paper

“Because of its small size (60 kDa), blinatumomab is characterized by a short serum half life of several hours, and so continuous intravenous infusion by portable mini-pumps is required.”

In the paper

“TF4 is a second bsAb built using the DNL method, directed against CD20 for the treatment of NHL.”

What the sources say

• Not checked yetcites [63] source

In the paper

“PAM-4, the parental anti-MUC-1 antibody has been shown to bind a MUC1 epitope that is not detected in normal pancreas but is expressed in 87% of invasive pancreatic adenocarcinomas, including early stage 1 disease. 64”

What the sources say

• Not checked yetcites [64] source